cstring.c

cstring

cstring.c

cstring is a command line tool for converting a text file into an array of C strings. It demonstrates a simple use of file and filter.

#include "root.h"
#include "file.h"
#include "filter.h"

strState

strState is the set of states to be used by stateFilter to process text.

strStart is the initial state, and the state at the start of each line.
strPrint is the state within each line, after opening quotes have been written.
strNStates counts the number of states, and is not itself a state.

typedef enum { strStart, strPrint, strNStates } strState;

strTable

strTable represents the finite state machine to be passed to stateFilter. Initialized by initFilterTable, it stores linked lists of rules for each state/character combination, in an order implementing longest match.

static filterRules *strTable[strNStates][NCHARS];

strRules

strRules describes the state transitions and text substitutions to be used by stateFilter to process text.

In state strStart, replace the empty string with an indented opening double quote \``, and move to statestrPrint`.
Staying in state strPrint, rewrite a double quote \`` as\``.
Staying in state strPrint, rewrite a backslash \\ as \\\\.
Staying in state strPrint, rewrite a tab as \t.
In state strPrint, append a closing double quote and a comma \,to the end of each line, and move to statestrStart`.

static filterRules strRules[] =
{
    { "", "\t\"", strStart, strPrint, 0 },
    { "\"", "\\\"", strPrint, strPrint, 0 },
    { "\\", "\\\\", strPrint, strPrint, 0 },
    { "\t", "\\t", strPrint, strPrint, 0 },
    { "\n", "\",\n", strPrint, strStart, 0 },    
    { 0 }
};

fileToCStrings

void fileToCStrings( const char *inputFile, const char *outputFile )
{
    FILE *fin, *fout;
    line *l;
    lineFilter filter;
    filterState state;

Clear "strTable" and initialize it with the rules specified by "strRules".

    initFilterTable( strTable, strRules, strNStates, YES );

filter is the struct to be passed to fileRead, to specify its filtering behavior. We use a single instance of the filter routine stateFilter, implementing the finite state machine strTable in initial state strStart. We are not providing a custom filt routine, so we set state.filt to null.

    filter.filt = stateFilter;
    filter.next = 0;
    filter.data = &state;
    state.table = strTable;
    state.state = strStart;
    state.filt = 0;

Open the input and output files, aborting on any error.

    fin = fileOpen( inputFile, "r", YES );
    fout = fileOpen( outputFile, "w", YES );

Read the input file into the linked list l, applying the filter filter, without detabbing. Write l to the output file, without applying any filters.

    l = fileRead( fin, &filter, 0 );
    fprintf( fout, "{\n" );
    fileWrite( fout, l, 0 );
    fprintf( fout, "\t0\n};\n" );

Close the input and output files, aborting on any error.

    fileClose( fin, YES );
    fileClose( fout, YES );

Free allocated memory. This is not necessary, because cstring is about to terminate, but finding memory leaks is one way to find bugs.

    lineListFree( l, markFree );

Now check that all allocated memory has been freed.

    mallocCount();    
}

main

main checks the command line arguments, and calls fileToCStrings.

int main( int argc, const char *argv[] )
{
    if ( argc != 3 )
        printf( "Usage: cstring input output\n" );
    else
        fileToCStrings( argv[1], argv[2] );
    return 0;
}